表面欠陥を起点とする延性破壊の機構と破断延性評価 : 単一穴を有する試験片の場合

概要

論文の詳細を見る
Tensile fracture tests of specimens having a single blind hole were carried out in order to investigate the mechanism of ductile fracture originating in a surface defect. Although a crack was initiated at the hole edge, the true stress-true strain curve of the holed specimen approximately coincided with that of the plain specimen with no hole untill the true stress reached a maximum value. In the deformation stage of the specimen after this stress value was reached, the growth behavior of the crack was not affected by the deformation of the hole. On the basis of these phenomena, parameter f_<ac> was defined by the ratio of crack area to minimum cross section of the specimen at which the true stress reached the maximum value, and the effect of hole size on the fracture ductility was examined using the parameter f_<ac>. The ture strain ε_c at the point of maximum true stress showed good correlation with the parameter f_<ac>, and the shear mode growth of the crack started unstably at this point. The relation between the fracture ductility ε_f and the parameter fαc was predicted from the relation between ε_c and f_<ac> and from the growth behavior of the crack. This relation coincided with the experimental results, and it was found that the fracture ductility ε_f of the present experiment is determined mainly by the starting conditions of unstable fracture and the growth behavior of the crack.
一般社団法人日本機械学会の論文
1995-12-25